Automatic fire alarm



F. A. SWAN.

AUTOMATIC FIRE ALARM. APPLICATION FILED Ausuzs, 1920.

v mama- 22,192. 15,436.

1 after set forth.

I 'tosend in a false alarm.

UNITED, STATES PATENT omce.

FREDERICK A.'SWAN, OF CLIFTONDALE; MASSACHUSETTS;-

AUTOMATIC an AIIARM. a

Specification of Reissucd Letters Patent.

Beissu'ed Aug; 22,1922.

Original No. 1,326,304, dated December 30, 1919, serial No. 178,121, filed July 2 i917. ma ma for reissue filed August 25, 1920, Serial nor teases.

To all "whom it may concern:

Be it known that'I, FREDERICK A. SWAN, a citizen of the United States, Zresidin at Cliftondale, in-the county of Essex and tate of Massachusetts, have invented anlmprovea ment in Automatic Fire Alarms, of which the following' description, in connection with the accompanying drawing, is a specification, like characters on thedrawing representing like parts. I i

This invention relates to automatic fire alarms and particularly to' the detector mechanism by which the fire alarm signal will be automatically sent in when fire conditions arise f i One object of the invention is to provide a differentiating detector device which will differentiate between a rise of temperature due to fire-conditions and arise of temperature due to other causes, and which will become operative to sound thealarm whenever fire. conditions arise, but which will be inoperative for this purpose when an excessivetemperature arises in the locality where the device is located, provided such excessive temperature is not the resultv of fire condi- Another object of the invention is to provide a'fire alarm system which will differentiatebetween a false alarm and a true alarm,'and also to provide a fire alarm apparatus which will give'indication when the circuit of the detector device is open or broken, and otherwise to improve fire alarm apparatus, all as will be more fully herein- I' accomplish these various objects by employing as .my detector a device in the nature of a differentiating thermo-electric battery which is connected to a relay that operates two 'circuit's and is constructed.

to cause. the relay to' close one circuit when fire conditions arise and to close the other circuit when it is subjected to a rise of temperature due to an abnormal cause, such, for instance, as an attempt i p g As is well known to those skilled the art, a thermo electric batteryhas the capability of generating a current in one direction when the temperature ofone set of the junctions thereof israised relative to that of the other junctions and of developinga current in the other-direction when the temperature of the first-named junctions is lowered relative to that of the other junctions. If, however, all

the junctions are of thesame temperature no current is generated. The thermo electric battery in myinvention is so sustained relative to the wallor ceiling of the'room 1n which it is placed that it will be uninfluencedl by the temperature of the wall or 'ceilin'gand will be influenced only by the temperature of the atmosphere, set are situated so that they are freely influenced by a, rapid change of temperature due The terminals of one;

to fire conditions, while the terminals of the other set are arranged so that theyv are af-.

fected only slightly by such rapid change of temperature. T he construction is such, how-' ever, that the terminals of the latter set will .be affected to a greater extent'by a rise 'of temperature due to such abnormal'conditions as thefapplication of heatdirectly to the detector device such as would be caused by applying a lighted match. thereto. Hence with this arrangement a current in one'di rection will be generated by thedetector device when it is subjected to a rise of temperature due to fireconditions while a current in the other direction will be generated when itis subjected'to a rise of temperature due'to some abnormal condition. The circuit of ,the detector-is connected to arelay.

arranged to close either one of two circuits, depending upon the direction of the current generated by the detector. Each'circuit will have a suitablesignal therein so that by observing the operation of the signal, it can be determined. whether the detector is being subjected to a rise of temperature due to fire conditions or to a rise of temperature due'to some other cause. The device is thus a differentiating detector. r f t In order to give an understanding of my invention, I have illustrated in thedrawings a selected embodiment thereof which will is sounded is indicated at 1, said circuit including av return wire 25. I have not shown I,

herein the details ofatfire alarm box, as this may be of any suitable construction adapted to be rendered operative. to send in i 1 1 isja vertical section through the i now be described, after which the no el I features will be pointed outin the appended the amt the alarm when theicir'cuit 1 is closedgbut' I have illustrated diagrammatically at 41 a city fire alarm box to which the circuit 1,95-

7 is connected, and it Will be understood that when sai'dicircuit 1', 25-15; closed, the box 41 will he actuated to send an alarm to head-z uarters over the usual signal circuit li A fire alarm box adaptedfor such use is illus .v

trated my Patent'NopL194 571', August 15, 1915,;111e circuitl is shown haying tyi'o noi nially-open contacts 2 and 3 therein which,a-tejcloseaby the;v operation of the tl li ri n"o-fele'ctric:v element of my device when fi atte i a a, 1

The contact 2 is shoivn as a stationary.

cg tact and the c'ontact 3 as a movable con t'ac saidc ntact .3 being herein illustrated i 3 toiiy'ard then contact 2,, wyhile'if current flows froth the coil inthe opposite. direction, said coil it'ill be turned oppositely to; swing its pewter away fr'ofn the, contact 2.

(The coil;5 of the relay, is connected a cirjcuitB, which; leads; to the thermos-electric electric'eleinent is Lin the nature of atherrnor.

electric battery'composed of a plurality of I I thermoelectric couples, each of hich corn; a prises two members 9:;and' 10 of different metals Whichare connected atthejunctions and 12.- I These electric couples are arranged in series as usual in atherln'o ele'c- 1 ,tr'i'c, battemjand are sustainediin a plate 13 'olfiiisulating material, the Inernbers f9 and 719 o'fleachfcouple extending transversely-1 throi1'gh the platefso that the junctions 12 are situated above the plate, while chairme- 3 tions are situated below the plate. This 'suiipo r'jtingplate 13 with the thfirmo-electric couple's secured-thereto is, "sustained, by a ba e ten a ceiling 1561' to a Wall or any other suit:

a.i fiyss l tb fi y59 y 13 from the base 14 ini ht be employed, 1

M sup ort. Ihe plate l3 is;;so secured to "t jej "base 14 that the junctions 121m l fron said plate I and ceiling and are ezgp d frj'eely to the atmos here, WVhile supportingfthe' plate h yeherein,showmthe ji late assecuredto a atent t y, are secured to the" base which extend through idh, The

-piece 14, preferably of insulating ma- 2 which is adaptedto, besc-rewed to "a posts by other Sam- 18 which extend throughthe plate and screw into the lower end of the posts.

With this construction the upper junctions 12 of the tl' ermo-electric battery a'r'esituated between the plate 13 a t e lewd r -spasm r m 1 0th the fifie and the Wall 15. Moreox erythey are freely exposed to the atmosphere and are subject to the full efiectof any atmospheric temperature. changes. J I

Means are proyided for protecting the lower junctions 11 that are "situated below temperature changes. This may be den 'inv various Ways, and as one simple construc-,

tion, have sho wn'a cap or coyerlfiwhich is secured to the plate 13 and.ihcloses the" junctions 11. Theprotecun mp' r 'coyer 1,9,Inay be ,made of metal, rubber, fiber or any suitable material.

' H i The opposite ends-tithe battery are ,con-

8 having the operating relay 7 therein.

, The operation of the device as thus tar,

describedis aslfolloy'vs So long as the atmospheric temperature in,

the locality offthje, thermo-electric element reinaihs substantially constant or sub:

jected to s lotvjariatio'n, the two Sets i A ,ns lland lQQWillhaVe substantially 1211. i r i. the saIne' te'infierature, and consequently no currentwill be generated in thecircuit 8. lx'sa result, the coil 5 till reinaininlits den: tral position and the Contact 3 will beseparated from thecontact 2. I I I t Y c If, however, there should be a rapid rise in atnilos-pheric temperature, such, for ,instance, as would result in the, case ofa tire, the exposed, junctions 12 will immediately feel thefeffe'ct of such change of tempera ture, and the 'teni15erature of, said 'unctions will rise accordingly Since the ot "er junctions 11 are protected by the protecting cover 19, they ,willbeinfluenced only gradually thesudtlei i ise intempe'ra'ture. In other Words, theefiect of the rapid rise in ternperature on the. junctions 11 .is retarded} Consequently, the xposed junctions 12 will soon acquire a temperature greater than the protected unctions, 11, and this dlfierence 1n temperaturegmll generate a current in the circuit 8i The current thus generated flows through the coil 5 in a direction to i cause said coil to, turn into a position to close the contact 3 aga nst the contact 2,

thus closing the circuit 1, 25, With the resultthatfihe b01541 Will operate to sendfthe,

aljarin The p rotection afforded by the 7.

cat @1948. intende 1w b p y a sufficient to protect thedjiinctions 11 against the infiuenc'e of "a "rapid rise in temperature, such as ould be caused by fire conditions, but 3 nt'o fone'e'nd. of the 1101- net v to fjfi'retect said ,fj nctiops. against the influence of a slow or gradual rise in tethi "the opposite side of the contact 3-from'the contact 2so thatwhen. the indicator Contact 3 swings, to the right,'Fig.'2./it "will engage perature. If, therefore, the temperature. in the locality of the thermo-electric element rises gradually or slowly, the relatiye tem-i peratureof the two sets ofjunctions llfand 12 will remain approximately the same, tmd

as a result there will not be current generated sufficient to operate the relay 7.

The device, therefore, is the one which. will differentiate between a rise oftemperature due to fire conditions and a rise of temperaandthe base "14. I I

, ilt somctimes happens that mischievous or malicious persons will,attempttosendin a other artificial. heat to 'the thermostatic element of an automatic fire alarm system. My

son doesmaliciously apply a match to the thermo electric element with the intention to send in a false alarm, the relay will operate to indicate the fact that the-device has been a false alarm would naturally apply the tions 11 will thus be raised over that of the are ata higher temperature than the junc- 5 totu'rn in adirection' to move the contact herein an additional contact 28 situated on thelcontact 2 3. Thiisfconta'ct 23 in a cirherein represented as an electrically oper ated bell 13 which will preferably be situated of thecircuit 24 and the indication a'theadthat it will be afiectedin one wa'y b y a sud den rise of temperature in the space surroundingisaid element, such, forinstance, as

would be due to "fire conditions, and will be wouldresult from applying a li false fire alarm by applying a match orfsomej 'plished by placing across said circuit 81 a apparatus isso-lconstructed that if any per-- tampered with, butwill not send in the I alarm. A person attempting thus to send in match or other ,heating'means to the bottom ofthe thermo-electric clement,that is',to the protecting plate 19. ll this is "done, the heat junctions12. This will cause a current to I I flow in the circuit8 in a direction oppesite to I, that inwhich it flows when the junctions 12 tions 11; and such currentwill cause the coil 3 away from'the contact'2. I have provided cuit 24; leading to any suitable signal appa ratus other than thefire alarm apparatus and;

at headquarters. The circuit ,24wmay 'b'e' con quarters of the fact that amaem n had'ben made to send in a false alarm 'My ther'moelectric element is, therefore, so constructed affected in another way by-a suddenrise in temperature locally applied to said element, such, for instance, as would? result'from the": application of a lighted match thereto; Thej unctions 12 are influenced (freelyby sudden v rise in temperature in the space surrounding thethermo-electric element, but since they are situated between the plate 13 and the base 14 they are protected from the full efit'ectof a local rapid rise in temperature, such as ghted match 7 to the device. The junctions 11, on the other hand, are protected from the rapid'rise in temperature in the space a surrounding the i element,- but are not protected from the local: rapid rise ill-temperature. I have alsoprovided herein means whereby a suitable indication will 'be 'made ifthe circuit 8 becomes openby the breaking of a wire or otherwise. This is herein. accom- '85- shunt circuit 26 having therein a relatively highresist'ance 27 and also a relatively small source o'f electricity, such, for instance, as a single dry cell 28. The resistance of thecir cuit 8 is relatively low and the high resistance 27 :willpreve nt any of. the current'generated by the thermo-electric 'devi'ce "from flowing through the shunt circuit 26, so that the presence of the shunt circuit does not interfere "with I the operation of the device Moreover, owing to the high'resistance 27 the amount of current which isimpressedon the circuit 26 by the dry cell28'will be GXCGBd-' ingly small,"and-xso' long as the circuit=is closed, the greater part of'such exceedingly I small current will fiow through the -thermo-' electric element rather than through the'coil 5 5 owing-to the greater resistance of the coil. The device is so adjusted that the amount 017C current from the battery 28- which is thus normally impressed on the @1135 is insufii cient to afi'ect the-relay so long as the circuit 8 is closed. Thecell 28 is so connectedin the circuit that the current generated-thereby tends to oppose the current generated bythe thermoelectric element when'the junctions 12 are at a highertemperature than the junctions ll and tends to flowthrough the coil. 5* in; a direction to causethecontact 3 to swing toward' the contact 23. If the circuit 8-should become broken betweenthe shunt circuit" 26 and the thermo-electric element, then all-'thecurrent generated by the bat-'- tery 28 will be impressed on the coil 5 and'120 this is sutlicient to actuate 'said coil to close the circuit 24, thereby ringing the bell 43 and giving indication atheadquarters that. the thermoelectric el'ement' needs attention.

My 4 device, therefore, operates not only to 1 2 5 differentiate between 'fire conditions and a rise'in temperature due toother c'au'ses, but also Y indicates at headquarters when the thermo-electric element is out of order or -has In actual practice therelay 7 will be made very sensitive so that it will respond to an exceedingly small current; wFigQQ of the drawings is intended to illustrate -arelay dia grammatically without any intention of sug gesting or indicating its actual structure.

I have herein shown a terminal connection between the terminalsand 2]. and the cir- I and thus insurea' 20 cuit 8 by which a good electric connection is always insured. Each of the terminals 20 and 21 is formedof twospring plates 29 each of which is provided with a T-shape'd head; Theends of the wires 8are'wound about the arms 30 of the head and the end of the wire l5 is then wrapped-about the body thereot, as shown at 31. By this means the two heads are drawn together slightly andthe resiliency'of them will tend to holdthe wire taut, good electrical connection;

Claims: I l 1. In a fire alarm, the combination with a dlfl erentiating thermoelectric battery comprising a plurality of connected thermo electric couples and means by which the:

junctidns of one set are freely exposed to rapid temperature changes in the space surroundingthe thermoelectric element but are i protected against local rapid temperature changes and the junctions'of the other set are protected against -rapid temperature changes in the spacefsurrounding the there mo-el'ectr-ic element but are influenced freely by a rapid local temperature change whereby currentwill be generated in one direction whenthe device is subjected to a rise'of temperature due to fire conditions and will be generated'in the other direction whensubjecte'd'toa localized rise of temperature, of two indicating circuits, and means to vclose one -circl'ii t when thecurren-t gener ated' by said thermo-electric element fiows in one. direction and the other circuit when said current flows-in the other direction. 7

,2. 'In a'detector device for fire alarm apparatus', the combinationwith a base member adapted to be secured to a wall or ceilingg 'iofa supporting iplatc sustained theree by, "but: separated: therefrom, a plurality of.

connected thermoelectric couples sustained by said 'supportingflplate, the. junctions" which are situated betweenflth'e plate and the base being exposed to the influence'of' rapid temperature changes;and means protecting the 's'etof junctions on the outside of said I supporting plate from the influence of rapid temperature changes.

3. In a detectordevice =fo'r fire alarm apparatus the combinationwith, a base mem- I ber adapted to-be secured to a wall *or -TceiL ing, of: a supporting plate sustained there-. by, but separated therefirompa plurality of connected thermoelectric couples sustainedb m id rting vplate, V the-junctions whichxare situated betweenthe plate and the base being exposed to the influence of rapid temperature changes, and a protecting cover inclosing the junctions on the outer side of the supporting plate.

4. A thermoelectric element/for fire alarm systemscomprising a pluralityof connected thermo-electric couples having twosets of; j u nctions, meansfor protecting the junctions of one set} against a local rapid rise of tem peraturewvhile permitting said junctions to be freely influenced by a rapidzrise of term perature in the space"surrounding said ele-' ment and for protecting the other set of junctions from, said latter sudden rise in temperature-'5 while. permitting the first named set of junctions to beinfluenced freely by the local rapid rise of temperatures 5. In a fire alarm apparatus;- the combination with a differentiating thermo-electric battery comprising a plurality of connected thermoelectric couples, means to protect the junctions} of one set. from rapid temperature changes in the space surrounding the battery while permitting said junctions to rent is developed in one direction in said bat--v teryv and the other circuit when current is developed in the other direction in said bat-.

tery, a city fire alarm box "connected to one ofsaid circuits and adapted to be. actuated. by the closing thereof to send an alarm'to headquarters, and -a signal connected to and;

actuated by the closing of the other circuit.

' 6. In a firejalarm apparatus, the combination with a differentiating thermo-electric battcry'com-prising a pluralityof connected thermo-electric couples and means by which said battery will develop current in one direction when it is subjected to a rise of temperature due to fire conditlons, and in the other direction when subjected to a rapid rise of temperature localized closely adja= cent said-battery, two indicating. circuits, means to closeione circuitwhen the battery develops current in .one direction and the other circuit when it develops current in the other direction, a city fire alarm box connected to one circuit to be actuated by the closing thereof to send an alarm to headcircuit. 7 r e v 7.. Ina fire alarm system, the combination with athermo-electric battery, of a sensi-. 'tive relay in circuit with said battery, and a permanently closed-electric battery shunt connected across the terminals of the relay and of relatively higher resistance than said circuit, for the purpose specified.

FREDERIGK A swan.

quarters, and a signal device in the other 

